docs: def plot_sino(self, ax=None, Ang=_def.LOSImpAng,
                    AngUnit=_def.LOSImpAngUnit, Sketch=True, dP=None,
                    dLeg=_def.TorLegd, draw=True, fs=None, wintit=None,
                    Test=True):
          """ Plot the sinogram of the vessel polygon, by computing its envelopp in a cross-section, can also plot a 3D version of it
  
          The envelop of the polygon is computed using self.Sino_RefPt as a reference point in projection space,
          and plotted using the provided dictionary of properties.
          Optionaly a small sketch can be included illustrating how the angle
          and the impact parameters are defined (if the axes is not provided).
  
          Parameters
          ----------
          proj :      str
              Flag indicating whether to plot a classic sinogram ('Cross') from the vessel cross-section (assuming 2D)
              or an extended 3D version '3d' of it with additional angle
          ax   :      None or plt.Axes
              The axes on which the plot should be done, if None a new figure and axes is created
          Ang  :      str
              Flag indicating which angle to use for the impact parameter, the angle of the line itself (xi) or of its impact parameter (theta)
          AngUnit :   str
              Flag for the angle units to be displayed, 'rad' for radians or 'deg' for degrees
          Sketch :    bool
              Flag indicating whether a small skecth showing the definitions of angles 'theta' and 'xi' should be included or not
          Pdict :     dict
              Dictionary of properties used for plotting the polygon envelopp,
              fed to plt.plot() if proj='Cross' and to plt.plot_surface() if proj='3d'
          LegDict :   None or dict
              Dictionary of properties used for plotting the legend, fed to plt.legend(), the legend is not plotted if None
          draw :      bool
              Flag indicating whether the fig.canvas.draw() shall be called automatically
          a4 :        bool
              Flag indicating whether the figure should be plotted in a4 dimensions for printing
          Test :      bool
              Flag indicating whether the inputs shall be tested for conformity
  
          Returns
          -------
          ax :        plt.Axes
              The axes used to plot
  
          """
          if Test:
              msg = "The impact parameters must be set ! (self.set_dsino())"
              assert not self.dsino['RefPt'] is None, msg
  
          # Only plot cross sino, from version 1.4.0
          dP = _def.TorPFilld if dP is None else dP
          ax = _plot.Plot_Impact_PolProjPoly(self, ax=ax, Ang=Ang,
                                             AngUnit=AngUnit, Sketch=Sketch,
                                             Leg=self.Id.NameLTX, dP=dP,
                                             dLeg=dLeg, draw=False,
                                             fs=fs, wintit=wintit, Test=Test)
          # else:
          # Pdict = _def.TorP3DFilld if Pdict is None else Pdict
          # ax = _plot.Plot_Impact_3DPoly(self, ax=ax, Ang=Ang, AngUnit=AngUnit,
                                        # Pdict=Pdict, dLeg=LegDict, draw=False,
                                        # fs=fs, wintit=wintit, Test=Test)
          if draw:
              ax.figure.canvas.draw()
          return ax